Heat dissipating plate, manufacturing method therefor and electronic device having the same

ABSTRACT

A heat dissipating plate includes a casing, a capillary structure layer, a support structure, and heat dissipating liquid. The casing includes a first substrate and a second substrate, which is disposed opposite to the first substrate to form a non-vacuum sealed cavity. The capillary structure layer is disposed in a first region of the non-vacuum sealed cavity and defines a first flow space. The support structure is disposed in a second region of the non-vacuum sealed cavity and defines a second flow space. The heat dissipating liquid is disposed in the non-vacuum sealed cavity, the liquid amount of which is more than 50% of the total capacity of the first flow space and the second flow space, and flows between the first flow space and the second flow space. The invention also provides a method for manufacturing the heat dissipation plate and an electronic device having the heat dissipation plate.

RELATED APPLICATIONS

The present application claims priority to Taiwanese Application Number108124221, filed Jul. 10, 2019, the disclosure of which is herebyincorporated by reference herein in its entirety.

BACKGROUND 1. Field of the Disclosure

This disclosure generally relates to a heat dissipating structure and,more particularly, to a heat dissipating plate, a manufacturing methodfor the heat dissipating plate and an electronic device having the heatdissipating plate.

2. Description of the Related Art

As the performance of portable electronic devices increases, heatgenerated by components of the portable electronic devices, such as dataprocessors, graphics processors and communication chips, increasesaccordingly. One trend of portable electronic devices is reducing theirweight and size. Therefore, it is very important to design a heatdissipating structure for portable electronic devices with moreeffective heat dissipation and smaller and lighter form factor.

Vapor chamber is a common heat dissipation structure in portableelectronic devices. A vapor chamber has an internal vacuum cavity.Inside the internal vacuum cavity there are a capillary structure layerand heat dissipating liquid (for example, pure water) less than 10% ofthe total capacity of the internal vacuum cavity. The heat dissipatingliquid is absorbed in the capillary structure layer to limit its flowcharacteristics. The heat dissipating liquid vaporizes to heatdissipating gas after absorbing heat and fill the cavity throughbuilt-in vapor channels to begin repeated cycles of vaporization andcondensation to achieve the purposes of thermal conduction and thermaldiffusion. In addition, such a vapor chamber requires a vacuumingequipment to vacuum the cavity to reduce the boiling point of the heatdissipating liquid and enable the heat dissipating gas to pass throughthe vapor channels rapidly. However, the vacuuming process increasesmanufacturing time and manufacturing cost. Furthermore, the heatdissipation of a vapor chamber is achieved by the flowing of the heatdissipating gas, whose heat dissipating efficiency is limited and lowerthan that of liquid cooling.

SUMMARY

The present disclosure is related to a heat dissipating plate that islight, thin and able to dissipate heat effectively. The heat dissipatingplate achieves small form factor and effective heat dissipation bycontrolling non-vacuum characteristics of the sealed cavity, the liquidamount of the heat dissipating liquid, and the configuration of thecapillary structure layer and the support structure.

The present disclosure provides a heat dissipating plate including acasing, a capillary structure layer, at least one support structure, anda heat dissipating liquid. The casing includes a first substrate and asecond substrate, wherein the first substrate and the second substrateare disposed opposite to each other to form a non-vacuum sealed cavity,wherein the non-vacuum sealed cavity defines a first region and a secondregion. The capillary structure layer is disposed in the first regionand defines a first flow space in the first region. The at least onesupport structure is disposed in the second region and provides supportbetween the first substrate and the second substrate, wherein the atleast one support structure defines a second flow space in the secondregion. The heat dissipating liquid is disposed in the non-vacuum sealedcavity and configured to flow between the first flow space and thesecond flow space. The liquid amount of the heat dissipating liquid ismore than 50% of a total capacity of the first flow space and the secondflow space. At least a part of the heat dissipating liquid in the firstflow space is configured to vaporize into a heat dissipating gas afterabsorbing heat. The heat dissipating gas is configured to diffuse froman end of the first flow space into the second flow space, and, aftercontacting with the heat dissipating liquid in the second flow space,condense and join the heat dissipating liquid in the second flow space.The heat dissipating liquid after the condensing and the joining isconfigured to flow in the second flow space and flow back into the firstflow space through another end of the first flow space.

The present disclosure is further related to an electronic deviceincluding the heat dissipating plate and a method for manufacturing theheat dissipating plate.

The present disclosure provides an electronic device including the heatdissipating plate, a circuit board, and an electronic component disposedon the circuit board. The heat dissipating plate is disposed on thecircuit board to dissipate the heat generated by the operation of theelectronic component.

The present disclosure provides a method for manufacturing a heatdissipating plate, including: providing a first substrate and a secondsubstrate, wherein the first substrate has a through hole, wherein afirst region and a second region are defined on the second substrate;disposing a capillary structure layer on the first region; disposing atleast one support structure on the second region; disposing a sealingglue layer on the second substrate, wherein the sealing glue layersurrounds the first region and the second region; attaching the firstsubstrate to the second substrate through the sealing glue layer so thatthe first substrate is positioned over the second substrate to form acavity between the first substrate and the second substrate, thecapillary structure layer defines a first flow space in the firstregion, and the at least one support structure defines a second flowspace in the second region; injecting a heat dissipating liquid into thecavity through the through hole, wherein a liquid amount of the heatdissipating liquid injected into the cavity is more than 50% of a totalcapacity of the first flow space and the second flow space; heating thefirst substrate or the second substrate for a predetermined timeduration to drive a part of air in the cavity from the cavity throughthe through hole; and sealing the through hole to convert the cavityinto a non-vacuum sealed cavity.

The sealed cavity of the heat dissipating plate manufactured by theaforementioned method is not vacuum, which requires neither vacuumingequipment nor soldering an additional liquid injection pipe to thethrough hole. Therefore, the aforementioned method can reduce the timeand cost for manufacturing the heat dissipating plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages, and novel features of the present disclosurewill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram of a heat dissipating plate according toan embodiment of the present disclosure.

FIG. 2 is a schematic diagram showing the internal structure of the heatdissipating plate in FIG. 1.

FIG. 3A is a cross-sectional view of the heat dissipating plate in FIG.2 along the line segment A-A.

FIG. 3B is a cross-sectional view of the heat dissipating plate in FIG.2 along the line segment B-B.

FIG. 4 is a partial cross-sectional view of an electronic deviceaccording to an embodiment of the present disclosure.

FIG. 5 is a schematic diagram showing the internal structure of theelectronic device in FIG. 4 with the heat dissipating plate in FIG. 1for absorbing heat.

FIG. 6 is a flow chart of a method for manufacturing a heat dissipatingplate according to an embodiment of the present disclosure.

FIGS. 7A to 7H are cross-sectional views illustrating a process formanufacturing the heat dissipating plate in FIG. 1.

DETAILED DESCRIPTION OF THE EMBODIMENT

It should be noted that, wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.The separate embodiments in the present disclosure below may be combinedtogether to achieve superimposed functions.

A heat dissipating plate, a method for manufacturing the heatdissipating plate, and an electronic device including the heatdissipating plate according to various embodiments of the presentdisclosure are discussed below. However, the embodiments of the presentdisclosure are merely examples describing the heat dissipating plate andthe method for manufacturing the heat dissipating plate provided by thepresent disclosure. The embodiments of the present disclosure have nopurpose to limit the scope of the present disclosure.

FIG. 1 is a schematic diagram of a heat dissipating plate 10 accordingto an embodiment of the present disclosure. FIG. 2 is a schematicdiagram showing the internal structure of the heat dissipating plate 10in FIG. 1. FIG. 3A is a cross-sectional view of the heat dissipatingplate 10 in FIG. 2 along the line segment A-A. FIG. 3B is across-sectional view of the heat dissipating plate 10 in FIG. 2 alongthe line segment B-B. Please refer to FIGS. 1, 2, 3A and 3B. The heatdissipating plate 10 includes a casing 12, a sealing glue layer 13, acapillary structure layer 14, a plurality of support structures 16, anda heat dissipating liquid 18. The thickness of the casing 12 can bethinner than 1 mm. The casing 12 includes a first substrate 12A and asecond substrate 12B. The first substrate 12A and the second substrateare 12B are disposed substantially parallel and opposite to each otherto form a non-vacuum sealed cavity 20. The first substrate 12A and thesecond substrate 12B are made of flexible metal material. The non-vacuumsealed cavity 20 defines a first region 20A and a second region 20B. Thesealing glue layer 13 connects the first substrate 12A and the secondsubstrate 12B. The sealing glue layer 13 surrounds the first region 20Aand the second region 20B to form the non-vacuum sealed cavity 20. Thecapillary structure layer 14 is disposed in the first region 20A anddefines a first flow space 22 in the first region 20A. In an embodiment,the capillary structure layer 14 is made of porous material. At leastone glue layer 15 attaches the capillary structure layer 14 to both thefirst substrate 12A and the second substrate 12B (as shown in FIG. 3A)or one of the first substrate 12A and the second substrate 12B. Themultiple inter-connected pores in the porous material define the firstflow space 22. The support structures 16 are disposed in the secondregion 20B and defines a second flow space 24 in the second region 20B.The support structures 16 connect the first substrate 12A and the secondsubstrate 12B. In addition, the support structures 16 provides supportbetween the first substrate 12A and the second substrate 12B to form agap between the first substrate 12A and the second substrate 12B. In thepresent embodiment, the support structures 16 are support strips spacedapart from each other and disposed in the second region 20B to define aplurality of flow channels 24A between the sealing glue layer 13 and thesupport structures 16. The flow channels 24A constitute the second flowspace 24. In another embodiment, the flow channels 24A can be defined bythe support structures 16 with other shapes together with the sealingglue layer 13. In an embodiment, the heat dissipating liquid 18 is aninsulating liquid with a boiling point lower than 50 degrees Celsius sothat the heat dissipating liquid 18 is not harmful to electriccomponents. The heat dissipating liquid 18 is disposed in the non-vacuumsealed cavity 20 for flowing between the first flow space 22 and thesecond flow space 24. The liquid amount of the heat dissipating liquid18 is more than 50% of the total capacity of the first flow space 22 andthe second flow space 24, as shown in FIG. 2. In the present embodiment,the total capacity of the first flow space 22 and the second flow space24 is the capacity of the non-vacuum sealed cavity 20 that can be filledwith the heat dissipating liquid 18.

Please refer to FIGS. 3A and 3B. In an embodiment, the sealing gluelayer 13 is constituted by a circular glue layer 13A and a waterproofglue layer 13B, and each support structure 16 is constituted by a stripglue layer 16A and a waterproof glue layer 16B. The strip glue layer 16Ais a double-sided glue layer having an opening 16C. The strip glue layer16A is connected between the first substrate 12A and the secondsubstrate 12B. The circular glue layer 13A and the strip glue layer 16Acan be double-sided glue layers made using the same material and thesame process (more details later). During the manufacturing of the heatdissipating plate 10, the opening 16C receives the waterproof glue layer16B to fixate the position of the waterproof glue layer 16B and preventthe waterproof glue layer 16B from being squeezed and flowing outward toreduce or block the flow channels 24A when the first substrate 12A andthe second substrate 12B are assembled together. In another embodiment,each support structure 16 can be formed by a waterproof glue layer 16Balone without the fixation by the opening 16C of the strip glue layer16A when the glue of the waterproof glue layer 16B is stable enough andnot prone to free flow.

In an embodiment, the sealing glue layer 13 can be formed by awaterproof glue layer 13B alone when the glue of the waterproof gluelayer 13B is stable enough and not prone to free flow. The sealing gluelayer 13 and the waterproof glue layer 16B of the support structure 16can be made using the same material and the same process (more detailslater).

The heat dissipating plate 10 is in a standing still state in FIG. 2.Therefore, due to gravity, all of the heat dissipating liquid 18 flowsto the lower part of the non-vacuum sealed cavity 20, and there is nobubble under the liquid surface of the heat dissipating liquid 18. Thelevel surface indicated by the number 18 in FIG. 2 is the liquid surfaceof the heat dissipating liquid 18 when the heat dissipating liquid 18 isstill.

FIG. 4 is a partial cross-sectional view of an electronic device 100according to an embodiment of the present disclosure. The electronicdevice 100 includes a heat dissipating plate 10, a circuit board 102,and an electronic component 104. The electronic component 104 isdisposed on the circuit board 102 and generates heat during operation.The electronic component 104 is a general processor, a graphicsprocessor, a communication chip, or any other electronic component thatgenerates heat. The heat dissipating plate 10 is the same as itscounterpart shown in FIGS. 1, 2 and 3A. The heat dissipating plate 10 isdisposed on the circuit board 102. The outer surface 17 of the secondsubstrate 12B corresponding to the first region 20A of the non-vacuumsealed cavity 20 is aligned to and in contact with the electroniccomponent 104.

FIG. 5 is a schematic diagram showing the internal structure of theelectronic device 100 in FIG. 4 with the heat dissipating plate 10 inFIG. 1 for absorbing heat. Please refer to FIGS. 4 and 5. When theelectronic component 104 generates heat H during operation, the heat Hdiffuse toward the outer surface 17 and enters the first region 20Athrough the second substrate 12B. Next, when the heat H is higher thanthe boiling point of the heat dissipating liquid 18 (for example, 50degrees Celsius), at least a part of the heat dissipating liquid 18 inthe first flow space 22 absorbs the heat H and vaporizes from heatdissipating liquid into heat dissipating gas, and generates higher steampressure. The heat dissipating gas diffuses from an end 22A of the firstflow space 22 into the second flow space 24 with a lower temperature(the directions of the diffusion are shown as hollow-headed arrows inFIG. 5), and, after contacting with the heat dissipating liquid 18 inthe second flow space 24, the heat dissipating gas condenses and joinsthe heat dissipating liquid 18 in the second flow space 24, therebydissipating the heat. Next, the heat dissipating liquid after thecondensing and the joining flows in the second flow space 24 (thedirections of the flowing are shown as solid-headed arrows in FIG. 5),thereby carrying the residual heat away from the heat source andreleasing the heat through thermal exchange with the externalenvironment to achieve the purpose of heat dissipation. Next, driven bythe attraction force generated by the capillary effect of the capillarystructure layer 14 and the vacancy caused by the spreading of the heatdissipating gas in the first flow space 22, the heat dissipating liquidafter the condensing and the joining flows back into the first flowspace 22 through another end 22B of the first flow space 22. Next, theaforementioned heat dissipating liquid flows into the region absorbingthe heat H, vaporizes from heat dissipating liquid to heat dissipatinggas, and repeats the aforementioned cycle of thermal exchange. In thepresent embodiment, the volume of the heat dissipating liquid in thesecond flow space 24 is larger than the volume of the heat dissipatinggas.

Compared to conventional vapor chambers, the cavity in the heatdissipating plate 10 in the previous embodiments is not vacuum, and theliquid amount of the heat dissipating liquid 18 is more than 50% of thetotal capacity of the first flow space 22 and the second flow space 24.When the heat dissipating liquid 18 absorbs the heat H, only a smallpart of the heat dissipating liquid 18 vaporizes into gas, while most ofthe heat dissipating liquid 18 remains in liquid state. Therefore, thethermal exchange cycles in the previous embodiments is achieved by thecirculation of the heat dissipating liquid after the condensing and thejoining between the first flow space 22 and the second flow space 24.The aforementioned circulation of the heat dissipating liquid after thecondensing and the joining in the thermal exchange cycles is propelledby a combined force. The combined force includes (1) the gas pressuregenerated when the heat dissipating liquid 18 vaporizes into the heatdissipating gas after absorbing heat, (2) the surface tension of thefirst substrate 12A and the second substrate 12B, (3) the attractionforce generated by the capillary effect of the capillary structure layer14, and (4) the gravity.

FIG. 6 is a flow chart of a method for manufacturing the heatdissipating plate 10 according to an embodiment of the presentdisclosure. FIGS. 7A to 7H are cross-sectional views illustrating aprocess for manufacturing the heat dissipating plate 10 in FIG. 1.Please refer to FIGS. 6 and 7A-7H. The process for manufacturing theheat dissipating plate 10 in FIG. 1 is described in details below.

Step S1: First, provide a first substrate 12A and a second substrate12B. The first substrate 12A has a through hole 21. A first region 20Aand a second region 20B are defined on the second substrate 12B, asshown in FIG. 7A.

Step S2: Dispose a circular glue layer 13A on a peripheral region of thesecond region 20B, and dispose at least one strip glue layer 16A on thesecond region 20B. Each strip glue layer 16A has an opening 16C, asshown in FIG. 7B.

Step S3: Dispose a capillary structure layer 14 on the first region 20Aof the second substrate 12B, as shown in FIG. 7C. In an embodiment, thecapillary structure layer 14 can be attached to the first region 20A ofthe second substrate 12B by a glue layer. In another embodiment, theexecution order of the steps S2 and S3 can be adjusted according to theactual arrangement of the manufacturing equipment. For example, executestep S3 to dispose the capillary structure layer 14 on the first region20A and then execute step S2 to dispose the circular glue layer 13A andthe strip glue layer 16A.

Step S4: Fill the opening 16C of each strip glue layer 16A with awaterproof glue by a glue dispenser (not shown in the figures) to form awaterproof glue layer 16B in order to form and dispose the at least onesupport structure 16 on the second region 20B. Meanwhile, apply thewaterproof glue on an outside of the circular glue layer 13A by a gluedispenser to form a waterproof glue layer 13B in order to form anddispose the sealing glue layer 13 on the second substrate 12B. Thesealing glue layer 13 surrounds the first region 20A and the secondregion 20B, as shown in FIG. 7D.

Step S5: Attach the first substrate 12A to the second substrate 12Bthrough the sealing glue layer 13 so that the first substrate 12A ispositioned over the second substrate 12B to form a cavity 20 between thefirst substrate 12A and the second substrate 12B so that the capillarystructure layer 14 defines a first flow space 22 in the first region 20Aand the at least one support structure 16 defines a second flow space 24in the second region 20B, as shown in FIG. 7E. In an embodiment, thefirst substrate 12A and the second substrate 12B can be connected toeach other by the strip glue layer 16A and the waterproof glue layer 16Bof the at least one support structure 16.

Step S6: Inject the heat dissipating liquid 18 into the cavity 20through the through hole 21 by a needle 19 of a liquid injectionmachine. The liquid amount of the heat dissipating liquid 18 injectedinto the cavity 20 is more than 50% of the total capacity of the firstflow space 22 and the second flow space 24, as shown in FIG. 7F. Inanother embodiment, the through hole 21 can be fabricated at anyposition that can communicate with the cavity 20 on the first substrate12A or the second substrate 12B for injecting the heat dissipatingliquid 18 into the cavity 20.

Step S7: Remove the needle 19 from the through hole 21 and heat thefirst substrate 12A or the second substrate 12B using a heating machine30 for a predetermined time duration to drive a part of the air A in thecavity 20 from the cavity 20 through the through hole 21, and keepanother part of the air in the cavity 20, as shown in FIG. 7G.

Step S8: Seal the through hole 21 with a sealing glue 23 to convert thecavity 20 into a non-vacuum sealed cavity 20, as shown in FIG. 7H.

The heat dissipating plate 10 provided by the present disclosurerequires neither vacuuming equipment nor soldering an additional liquidinjection pipe to the through hole 21. Therefore, the time and cost formanufacturing the heat dissipating plate can be reduced. In addition,the liquid amount of the heat dissipating liquid 18 in the cavity 20 ofthe heat dissipating plate 10 is more than 50% of the total capacity ofthe first flow space 22 and the second flow space 24, which enables moreeffective thermal exchange for rapid heat dissipation.

Although the disclosure has been explained in relation to its preferredembodiment, it is not used to limit the disclosure. It is to beunderstood that many other possible modifications and variations can bemade by those skilled in the art without departing from the spirit andscope of the disclosure as hereinafter claimed.

What is claimed is:
 1. A heat dissipating plate, comprising: a casing,comprising a first substrate and a second substrate, wherein the firstsubstrate and the second substrate are disposed opposite to each otherto form a non-vacuum sealed cavity, wherein the non-vacuum sealed cavitydefines a first region and a second region; a capillary structure layer,disposed in the first region, and defines a first flow space in thefirst region; at least one support structure, disposed in the secondregion, and providing support between the first substrate and the secondsubstrate, wherein the at least one support structure defines a secondflow space in the second region; and a heat dissipating liquid, disposedin the non-vacuum sealed cavity, and configured to flow between thefirst flow space and the second flow space, wherein the liquid amount ofthe heat dissipating liquid is more than 50% of a total capacity of thefirst flow space and the second flow space, at least a part of the heatdissipating liquid in the first flow space is configured to vaporizeinto a heat dissipating gas after absorbing heat, the heat dissipatinggas is configured to diffuse from an end of the first flow space intothe second flow space, and, after contacting with the heat dissipatingliquid in the second flow space, condense and join the heat dissipatingliquid in the second flow space, and the heat dissipating liquid afterthe condensing and the joining is configured to flow in the second flowspace and flow back into the first flow space through another end of thefirst flow space.
 2. The heat dissipating plate of claim 1, wherein athickness of the casing is thinner than 1 mm, wherein the firstsubstrate and the second substrate are disposed substantially paralleland opposite to each other, wherein the first substrate and the secondsubstrate are made of flexible metal material.
 3. The heat dissipatingplate of claim 1, wherein the flowing of the heat dissipating liquidafter the condensing and the joining is propelled by a combined force,wherein the combined force comprises a gas pressure generated when theheat dissipating liquid vaporizes into the heat dissipating gas afterabsorbing heat, a surface tension of the first substrate and the secondsubstrate, an attraction force generated by a capillary effect of thecapillary structure layer, and a gravity.
 4. The heat dissipating plateof claim 1, wherein a volume of the heat dissipating liquid in thesecond flow space is larger than a volume of the heat dissipating gas,wherein the heat dissipating liquid is an insulating liquid with aboiling point lower than 50 degrees Celsius.
 5. The heat dissipatingplate of claim 1, further comprising a sealing glue layer, wherein thesealing glue layer connects the first substrate and the second substrateand surrounds the first region and the second region to form thenon-vacuum sealed cavity.
 6. The heat dissipating plate of claim 5,wherein the total capacity of the first flow space and the second flowspace is a capacity of the non-vacuum sealed cavity that can be filledwith the heat dissipating liquid.
 7. The heat dissipating plate of claim1, wherein the capillary structure layer is made of porous material,wherein at least one glue layer attaches the capillary structure layerto at least one of the first substrate and the second substrate.
 8. Theheat dissipating plate of claim 1, wherein the at least one supportstructure comprises a plurality of support strips, wherein the supportstrips are spaced apart from each other and disposed in the secondregion to define a plurality of flow channels, wherein the flow channelsconstitute the second flow space.
 9. An electronic device, comprisingthe heat dissipating plate of claim
 1. 10. A method for manufacturing aheat dissipating plate, comprising: providing a first substrate and asecond substrate, wherein the first substrate has a through hole,wherein a first region and a second region are defined on the secondsubstrate; disposing a capillary structure layer on the first region;disposing at least one support structure on the second region; disposinga sealing glue layer on the second substrate, wherein the sealing gluelayer surrounds the first region and the second region; attaching thefirst substrate to the second substrate through the sealing glue layerso that the first substrate is positioned over the second substrate toform a cavity between the first substrate and the second substrate, thecapillary structure layer defines a first flow space in the firstregion, and the at least one support structure defines a second flowspace in the second region; injecting a heat dissipating liquid into thecavity through the through hole, wherein a liquid amount of the heatdissipating liquid injected into the cavity is more than 50% of a totalcapacity of the first flow space and the second flow space; heating thefirst substrate or the second substrate for a predetermined timeduration to drive a part of air in the cavity from the cavity throughthe through hole; and sealing the through hole to convert the cavityinto a non-vacuum sealed cavity.
 11. The method of claim 10, wherein thestep of disposing the sealing glue layer on the second substrate furthercomprises: disposing a circular glue layer on a peripheral region of thesecond region; and applying a waterproof glue on an outside of thecircular glue layer to form the sealing glue layer.
 12. The method ofclaim 10, wherein the step of disposing the at least one supportstructure on the second region further comprises: disposing at least onestrip glue layer on the second region, wherein each said strip gluelayer has an opening; and filling the opening of each said strip gluelayer with a waterproof glue to form the at least one support structure.